The invention relates to a stackable archive container made from a cardboard sheet, principally comprising a back wall and, when viewed in the stacked state, two side walls, a top wall and a bottom wall, wherein a pivoting closing flap is connected to one of the top or bottom walls.
Such archive containers are used on a large scale for storing archive boxes, files, dossiers and the like. In such an archive container four or six archive boxes can, for example, be stored, depending on the size of the boxes. Such archive containers can easily be moved and are self-stacking, and can also be placed back to back in an area. Accordingly, no vertical wall is necessary for the fastening of shelf supports to carry shelves or the like.
To support the top wall and to place the archive containers in the correct position relative to one another during the stacking operation, in certain cases the top wall and bottom wall are provided with a few slots which run parallel to the side walls and are positioned therebetween. The slots in the top wall serve to accommodate the projecting tongues of an intermediate dividing wall which on the underside is provided with recesses into which the tongues of an intermediate subjacent wall can be accommodated. This intermediate wall is a double wall and is made from the same cardboard sheet as the rest of the archive container.
A drawback of the known archive containers is that only a limited number of containers can be stacked on top of one another, due to the fact that their vertical walls can absorb only a certain load. This is particularly prevalent when the containers are stored in a damp area, where the damp cardboard loses its structural rigidity, and consequently tends to give way more quickly under a load.
U.S. Pat. No. 2,024,075 shows the possibility of reinforcing the edges of separate panels of a container by pushing profiles onto them. Here, however, such formed profiles are adapted and the walls of the container made in such a way that crenellated parts of the profiles provided along the four edges of a side wall fit into complementally crenellated parts of the profiles provided on the bottom wall, the rear wall, the top wall and the front wall. A rod is then pushed through two profiles that fit into one another so as to connect each edge of a side wall with the edges of the other walls. The side walls, therefore, do not form an integral whole with the other walls so that the resultant container is not made from one single sheet. Furthermore, the fitting of the profiles onto the various edges and the connecting together of the separate walls of a single container is time consuming and labour intensive. Provision is also not made for the joining together of adjacent containers.
From U.S. Pat. No. 3,989,157 and GB 1,0732,371 it is also known to reinforce the edges of panels by pushing profiles onto them. Here, however, the profiles are also used at the same time for joining the individual panels to one another, with the panels similarly not forming part of a unitary folded sheet.
According to a first aspect of the invention there is provided a stackable archive container folded from a cardboard blank of a predetermined thickness and comprising, in the folded state, a pair of side walls, a top wall, a bottom wall and a rear wall, and preferably a front closure flap hinged to the top or bottom walls, characterized in that rigid reinforcing bars are fitted to vertical side edges of the side walls and/or the rear wall at the comers of the container, the reinforcing bars extending the length of the side edges and each of the bars having at least one U-shaped profile for embracing the side edges in a snug push fit.
It will be clear that the reinforcing profiles are positioned between the top and bottom walls, in which case a few layers of cardboard will be sandwiched between the ends of the reinforcing profiles of two archive containers positioned above one another. However, in practice this does not present problems, with the cushioning effect provided by the cardboard enhancing the sturdiness of the stacked structure.
In a preferred form of the invention, the one or more U-shaped profiles of the reinforcing bars are configured to reinforce and to join together the vertical side edges of adjacent containers.
Preferably, at least one, and more preferably both of the opposed inner surfaces of the legs of the U-shaped profile are formed with wall-gripping ribs extending in the longitudinal direction of the bar for penetrating into the outer surfaces of the cardboard to provide a strong connection between the rib and the cardboard. These ribs will then penetrate slightly into the surface of the cardboard, so that the connection is enhanced between the reinforcing profile and the cardboard.
Advantageously, the ribs have a sawtooth profile arranged so that the surface of each rib directed towards the opening of the U-shaped profile defines a shallow angle relative to the leg of the U from which the ribs extend. As a result thereof the reinforcing profile can be pushed relatively easily onto a wall of the archive container, but the saw-tooth ribs will prevent the profile from slipping or sliding off the wall.
In one form of the invention, the reinforcing bars include reinforcing bars having a single U-shaped profile sized to accommodate a double wall thickness of cardboard in a snug push fit, the double wall thickness arising from either double wall thickness side walls or from adjacent single wall thickness side or rear walls of containers joined side-by-side or back-to-back.
The reinforcing bars may further include reinforcing bars having a double U-shaped profile in a side-by-side W configuration, for allowing side walls of adjacent containers to be connected together, whilst simultaneously being reinforced.
Advantageously, the side walls of the container have a double wall thickness, and each of the U-shaped profiles are sized to accommodate the side edges of the adjacent side walls in a snug push fit.
The reinforcing bars may still further include bars having a double U-shaped profile in a back-to-back H-configuration for allowing four containers to be connected together at their rear walls, whilst simultaneously being reinforced.
Typically, each of the rear walls have a single wall thickness, and each of the U-shaped profiles are arranged to accommodate the rear walls of a pair of containers in a back-to-back configuration.
The containers may be formed with complementary aligning formations for allowing them to be aligned when stacked on top of one another such that the reinforcing bars in the aligned stack define rigid co-linear reinforcing arrays allowing the overall height of the stack to be increased.
The reinforcing bars are preferably made of aluminium, which may be extrusion moulded.
The invention extends to a method of forming a stackable archive container comprising the steps of folding the container from a cardboard blank to provide a pair of side walls, a top wall, a bottom and a rear wall, and fitting rigid reinforcing bars to vertical side edges of the side walls and/or the rear wall at the corners of the container, the reinforcing bars extending the length of the side edges and each of the bars having at least one U-shaped profile for embracing the side edges in a snug push fit.
In a preferred form of the invention, the method includes the further step of joining together adjacent containers along their vertical side edges using the one or more U-shaped profiles of the reinforcing bars to embrace exposed adjacent side edges of adjacent containers in a snug push fit.
Conveniently, the method further includes the steps of stacking the containers on top of one another in an aligned configuration such that the reinforcing bars in the aligned stack define rigid co-linear reinforcing arrays allowing the overall height of the stack to be increased.